How Far Apart Rafters For Metal Roof

The typical spacing standards for residential and commercial buildings are about 1 to 2 foot.

How far apart rafters for metal roof.

The support system for the roof is comprised of ridgepole and rafters or purlins. All roof rafters should be identical so follow the same steps to measure the plumb cut tail cut and birdsmouth cut. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel. Wider panels allow for greater spacing between rafters.

To determine how far apart to set rafters measure the width of the metal panel and then the width of the first hill and valley of the panel. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. If you have a simple gable shed roof then using 2 4 rafters makes more sense unless you have a very large shed. At this point you ve cut 1 roof rafter.

Depending on the size of your structure you will need to cut several or many more. In this example the section of roof is 20 feet wide and 14 feet from the fascia to the peak. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. Repeat the process for your other rafters.

Other relevant factors include the type of wood being used for the rafters the size of the rafters and the load that the rafters need to support.